Low melt flow branched ionomers

ABSTRACT

Embodiments of the present invention include a branched aromatic ionomer, and a process of making it, by co-polymerizing a first monomer comprising an aromatic moiety and an unsaturated alkyl moiety and a second monomer represented by the general formula:
 
[R-A Z ] y -M X  
 
wherein R is a hydrocarbon chain having from 2 to 40 carbons and at least one polymerizable unsaturation; A is an anionic group; M is a cationic group; Z is −1 or −2; X is +1, +2, +3, +4, or +5; and y is an integer having a value of from 1 to 4. The branched aromatic ionomer has a melt flow index ranging from 1.0 g/10 min. to 13 g/10 min. Optionally the melt flow index ranges from 1.3 g/10 min. to 1.9 g/10 min.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional of U.S. Provisional ApplicationSer. No. 61/420,460 and this application is also a continuation-in-partof U.S. patent application Ser. No. 12/500,701, filed Jul. 10, 2009,which is a continuation of U.S. patent application Ser. No. 11/932,053,filed Oct. 31, 2007 (now U.S. Pat. No. 7,601,788), which is acontinuation of U.S. patent application Ser. No. 11/638,200, filed Dec.13, 2006 (now U.S. Pat. No. 7,309,749), which is a divisional of U.S.patent application Ser. No. 11/043,595, filed Jan. 26, 2005 (now U.S.Pat. No. 7,179,873).

FIELD

Embodiments of the present invention generally relate to branchedionomers having a low melt flow rate.

BACKGROUND

In the art of preparing polymers, it can be desirable to impart to orincrease the branching of polymer chains. Increased branching may impartphysical property changes to the polymer, such as increased strength,higher temperature performance, and improved hardness, for example. Insome instances, increased branching may improve properties such aselastomeric performance and abrasion resistance.

Ionomers are known to be useful in many applications. For example, apolyester ionomer dyeability enhancer may be derived from the reactionresidue of an aryl carboxylic acid sulfonate salt, an aromaticdicarboxylic acid, an aliphatic dicarboxylic acid, an aliphatic diol orany of their ester-forming derivatives. A photocurable dental cement maybe prepared using a photocurable ionomer, which is defined as a polymerhaving sufficient pendent ionic groups to undergo a setting reaction inthe presence of a reactive filler and water, and sufficient pendentpolymerizable groups to enable the resulting mixture to be polymerized,e.g., cured upon exposure to radiant energy.

However, efforts continue to improve physical properties of polymers.

SUMMARY

Embodiments of the present invention include a branched aromatic ionomerthat is the product of co-polymerizing a first monomer comprising anaromatic moiety and an unsaturated alkyl moiety and a second monomerrepresented by the general formula:[R-A^(Z)]_(y)-M^(X)wherein R is a hydrocarbon chain having from 2 to 40 carbons and atleast one polymerizable unsaturation; A is an anionic group; M is acationic group; Z is −1 or −2; X is +1, +2, +3, +4, or +5; and y is aninteger having a value of from 1 to 4. The branched aromatic ionomer hasa melt flow index ranging from 1.0 g/10 min. to 13 g/10 min. Optionallythe melt flow index ranges from 1.3 g/10 min. to 1.9 g/10 min.

In an embodiment, either by itself or in combination with otherembodiments, the first monomer can be selected from the group consistingof styrene, alphamethyl styrene, t-butylstyrene, p-methylstyrene, vinyltoluene, and mixtures thereof.

In an embodiment, either by itself or in combination with otherembodiments, the second monomer is selected from the group consistingof: zinc diacrylate, zinc dimethacrylate, zinc di-vinylacetate, zincdi-ethylfumarate: copper diacrylate, copper dimethacrylate, copperdi-vinylacetate, copper di-ethylfumarate; aluminum (III) isopropoxide,aluminum triacrylate, aluminum trimethacrylate, aluminumtri-vinylacetate, aluminum tri-ethylfumarate; zirconium tetraacrylate,zirconium tetramethacrylate, zirconium tetra-vinylacetate, zirconiumtetra-ethylfumarate, zirconium (IV) butoxide; and mixtures thereof.

In an embodiment, either by itself or in combination with otherembodiments, the second monomer is present in amounts from 10 to 10,000ppm, optionally from 100 to 2,500 ppm.

In an embodiment, either by itself or in combination with otherembodiments, the ionomer exhibits a weight average molecular weight from255,000 Dalton to 330,000 Dalton.

In an embodiment, either by itself or in combination with otherembodiments, the ionomer exhibits a polydispersity from 1.8 to 3.1.

In an embodiment, either by itself or in combination with otherembodiments, the ionomer exhibits a tensile strength at yield from 3,400psi to 8,000 psi.

In an embodiment, either by itself or in combination with otherembodiments, the ionomer exhibits a tensile strength at break from 3,200psi to 7,900 psi.

In an embodiment, either by itself or in combination with otherembodiments, the ionomer exhibits a flexural strength from 6,000 psi to16,500 psi.

In an embodiment, either by itself or in combination with otherembodiments, the ionomer exhibits a flexural modulus from 410,000 psi to490,000 psi.

In an embodiment, either by itself or in combination with otherembodiments, the invention includes a blown film formed by the ionomer.

In an embodiment, either by itself or in combination with otherembodiments, the invention includes a foamed article formed by theionomer.

Embodiments of the present invention include a process for preparing abranched aromatic ionomer that includes co-polymerizing a first monomercomprising an aromatic moiety and an unsaturated alkyl moiety and asecond monomer represented by the general formula:[R-A^(Z)]_(y)-M^(X)wherein R is a hydrocarbon chain having from 2 to 40 carbons and atleast one polymerizable unsaturation; A is an anionic group; M is acationic group; Z is −1 or −2; X is +1, +2, +3, +4, or +5; and y is aninteger having a value of from 1 to 4. The branched aromatic ionomer hasa melt flow index from 1.0 g/10 min. to 13 g/10 min, optionally from 1.3g/10 min. to 1.9 g/10 min.

In an embodiment, either by itself or in combination with otherembodiments, the second monomer is prepared prior to theco-polymerization by admixing components in-line to a reactor or in-situin a reactor.

In an embodiment, either by itself or in combination with otherembodiments, the second monomer is prepared in-situ in the firstmonomer.

In an embodiment, either by itself or in combination with otherembodiments, the second monomer is prepared from an unsaturated acid oranhydride and a metal alkoxide.

In an embodiment, either by itself or in combination with otherembodiments, the second monomer is prepared by reacting an organic acidor an anhydride with a metal or metal salt.

In an embodiment, either by itself or in combination with otherembodiments, the first monomer is selected from the group consisting ofstyrene, alphamethyl styrene, t-butylstyene, p-methylstyrene, vinyltoluene, and mixtures thereof.

In an embodiment, either by itself or in combination with otherembodiments, the second monomer is selected from the group consistingof: zinc diacrylate, zinc dimethacrylate, zinc di-vinylacetate, zincdi-ethylfumarate: copper diacrylate, copper dimethacrylate, copperdi-vinylacetate, copper di-ethylfumarate; aluminum (III) isopropoxide,aluminum triacrylate, aluminum trimethacrylate, aluminumtri-vinylacetate, aluminum tri-ethylfumarate; zirconium tetraacrylate,zirconium tetramethacrylate, zirconium tetra-vinylacetate, zirconiumtetra-ethylfumarate, zirconium (IV) butoxide; and mixtures thereof.

In an embodiment, either by itself or in combination with otherembodiments, the process includes the step of admixing the first andsecond monomers prior to or at the time of the co-polymerization.

In an embodiment, either by itself or in combination with otherembodiments, the first and second monomers are admixed with a solventprior to co-polymerization.

In an embodiment, either by itself or in combination with otherembodiments, the process includes the steps of foaming the ionomer andusing said foamed ionomer to make an article.

In an embodiment, either by itself or in combination with otherembodiments, the process includes the step of making an article withsaid ionomer.

In an embodiment, either by itself or in combination with otherembodiments, the ionomers are admixed with additives prior to being usedin end use applications, and wherein the additives are selected from thegroup consisting of fire retardants, antioxidants, lubricants, blowingagents, UV stabilizers, antistatic agents, and combinations thereof.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates blown film tensile properties of various neat polymersamples.

FIG. 2 illustrates blown film tensile properties of various blendedpolymer samples.

FIG. 3 illustrates hauloff force vs hauloff speed of various neatpolymer samples.

DETAILED DESCRIPTION

Branched aromatic ionomers may be formed by co-polymerizing a firstmonomer and a second monomer. The first monomer generally includes anaromatic moiety and an unsaturated alkyl moiety. For example, suitablemonomers having an aromatic moiety and an unsaturated alkyl moiety mayinclude monovinylaromatic compounds, such as styrene, as well asalkylated styrenes wherein the alkylated styrenes are alkylated in thenucleus or side-chain (e.g., alphamethyl styrene, t-butylstyrene,p-methylstyrene, and vinyl toluene) and combinations thereof.

The second monomer generally includes an ionic moiety and at least oneunsaturated moiety. The ionic moiety generally includes at least twoionizable groups (one group that ionizes to form cations and one thationizes to form anions). In one or more embodiments, the group thationizes to form cations, hereinafter “cationic group,” is a mono-valentgroup. In other embodiments, the cationic group is poly-valent and onecapable of forming bridges to other molecules in the presence of ions ofa suitable type and concentration. When the cationic group is amono-valent group, it may be selected from mono-valent metals or aquaternary ammonium ion forming compounds, for example. Suitable metalsinclude sodium, potassium, cesium, silver and combinations thereof, forexample. Suitable quaternary ammonium compounds include ammoniumchloride, methyl ammonium chloride, diethyl ammonium chloride andcombinations thereof, for example. When the cationic group is onecapable of forming bridges to other molecules in the presence of ions ofa suitable type and concentration, it may be selected from groups thationize to form cations having a valence of +2 or higher. In one or moreembodiments, the cationic group may be selected from metals having anoxidation state of +2 or higher. Suitable metals include zinc, copper,lead, calcium, magnesium, zirconium, aluminum, and combinations thereof,for example.

The second ionizable group is generally an organic group that ionizes toform an anion having a coordination charge of −1 or lower. Suitablegroups include anions of amines, carboxylic acids, sulfonic acids,phosphonic acids, thioglycolic acids and combinations thereof, forexample. When the cationic group has a valence of greater than +1, thefirst and second ionizable groups may form a bridge.

Further, the anionic group generally includes at least one polymerizableunsaturated moiety. In some embodiments, there is only one polymerizableunsaturated moiety. In other embodiments, there may be two or more suchmoieties. The unsaturated moiety may be a terminal or non-terminalcarbon-carbon double bond, for example.

Exemplary compounds useful as the second monomer may be prepared with ametal cation and an organic anion having at least one unsaturation.Suitable compounds that may be used as the second monomer include anyhaving a general formula:[R-A^(Z)]_(y)-M^(X)wherein R is a hydrocarbon chain having from 2 to 40 carbons and atleast one polymerizable unsaturation; A is an anionic group; M is acationic group; Z is −1 or −2; X is +1, +2, +3, +4, or +5; and y is aninteger having a value of from 1 to 4. When y is 1, R may have one ormore polymerizable unsaturations. In embodiments where y is 1, R mayhave two or more unsaturations and the unsaturations will either be onseparate chains or else sufficiently far apart on a single chain toallow for polymerization without substantial steric hindrance. In someembodiments, (y*Z)+X=0, that is, only anionic groups having apolymerizable unsaturation will be coordinated to the M group. However,if is within the scope of the claims that additional groups not having apolymerizable unsaturation may be coordinated to the M group, there maystill be at least two polymerizable unsaturations coordinated to the Mgroup in addition to any other coordinated groups.

Compounds that may be used as the second monomer include, but are notlimited to, zinc diacrylate, zinc dimethacrylate, zinc di-vinylacetate,zinc di-ethylfumarate, and the like; copper diacrylate, copperdimethacrylate, copper di-vinylacetate, copper di-ethylfumarate, and thelike; aluminum triacrylate, aluminum trimethacrylate, aluminumtri-vinylacetate, aluminum tri-ethylfumarate, and the like; zirconiumtetraacrylate, zirconium tetramethacrylate, zirconiumtetra-vinylacetate, zirconium tetra-ethylfumarate and combinationsthereof, fore example. For compounds having monovalent cationic groups,the second monomer may be sodium acrylate, sodium methacrylate, silvermethacrylate and combinations thereof, for example.

These compounds and any compound useful as the second monomer may beprepared by any method known to one skilled in the art. For example, thesecond monomer may be prepared by, for example, reacting an organic acidor an anhydride with a metal or metal salt. When the cation group ispolyvalent, then the organic acid and the polyvalent metal may bereacted under conditions sufficient to prepare a bridge between theanionic group and the cationic group.

The monomers used to prepare the branched aromatic ionomers may interactin several ways to affect the physical properties of the ionomers. Forexample, the monomers may form covalent bonds due to the polymerizationof the unsaturated moieties. Further, the monomers may interact to forma bridge, wherein a polyvalent cationic group is coordinated to twoanionic groups which are integrated into the backbones of at least twoseparate chains, for example. This coordination may, in effect,crosslink the two chains thereby increasing that segment's totaleffective molecular weight to the sum of the two chains. In addition,the monomers may interact to form multiple bridges as describedimmediately above. The more crosslinking that occurs, the less flexiblethe three dimensional structure of the ionomer, which may result inlower melt flow values and increased melt strength.

Furthermore, when the cationic groups are mono-valent, the ionicmoieties, while not fully bridged, may still associate due tohydrophobic-hydrophilic forces. In these embodiments, this weaker butstill measurable force may result from the comparatively non-polarhydrophobic, non-ionic parts of the molecule being mutually attractedand repelled from the polar hydrophilic ionic parts of the ionomer.These forces are more noticeable as the proportion of the second monomeris increased in concentration.

Both the amount of second monomer and the type of interaction with thefirst monomer will dictate the amount of second monomer used. Therefore,in some embodiments where the interaction is weak, such as when thecationic group of the second monomer is mono-valent, and a significantamount of effect is desired from the second monomer, the branchedionomers are prepared with a comparatively large amount of the secondmonomer. For example, the ratio of first monomer to second monomer maybe from about 999:1 to about 40:60, or from about 95:5 to about 50:50,or from about 90:10 to about 60:40 or from about 80:20 to about 70:30,for example.

Where the interaction is very strong, such as when the cationic group isdi- or tri-valent, or only small changes to the properties of theionomer due to the second monomer are desired, the amount of the secondmonomer is quite small. For example, the amount of the second monomermay be from 10 parts per million “ppm” to 10,000 ppm, optionally from100 ppm to 5000 ppm, optionally from 250 ppm to 2500 ppm, optionallyfrom 500 ppm to 1000 ppm for example.

The branched aromatic ionomer may be prepared by co-polymerizing thefirst and second monomers. The polymerization may be carried out usingany method known to those of ordinary skill in the art of performingsuch polymerizations. (See, U.S. Pat. No. 5,540,813; U.S. Pat. No.3,660,535 and U.S. Pat. No. 3,658,946, which are incorporated byreference herein.) For example, the polymerization may be carried out byusing a polymerization initiator.

Examples of the polymerization initiators include radical polymerizationinitiators, such as benzoyl peroxide, lauroyl peroxide, t-butylperoxybenzoate and 1,1-di-t-butylperoxy-2,4-di-t-butylcyclohexane andcombinations thereof, for example. The amount of the polymerizationinitiator may be from about 0 to about 1 percent by weight of themonomers, or from about 0.01 to about 0.5 percent by weight of themonomers or from about 0.025 to about 0.05 percent by weight of themonomers, for example.

Alternatively, rather than using an initiator, the ionomer may beprepared using heat as an initiator. In yet another embodiment, theionomer may be prepared using a non-conventional initiator, such as ametallocene catalyst as is disclosed in U.S. Pat. No. 6,706,827, whichis incorporated by reference herein.

In one or more embodiments, the monomers may be admixed with a solventand then polymerized. In other embodiments, one of the monomers may bedissolved in the other and then polymerized. In still other embodiments,the monomers may be fed concurrently and separately to a reactor, eitherneat or dissolved in a solvent, such as mineral oil. In yet anotherembodiment, the second monomer may be prepared in-situ or immediatelyprior to the polymerization by admixing the raw material components,such as an unsaturated acid or anhydride and a metal alkoxide, in-lineor in the reactor.

In certain embodiments, the ionomers may be admixed with additives priorto being utilized in end use applications. Any additive known to beuseful to those of ordinary skill in the art of preparing ionomers to beuseful may be used with the branched ionomers. For example, the ionomersmay be admixed with fire retardants, antioxidants, lubricants, blowingagents, UV stabilizers, antistatic agents and combinations thereof, forexample.

The ionomers may exhibit a melt flow index (MFI) (as measured by ASTM D1238 condition 200° C./5 kg) of from about 1 g/10 min. to about 40 g/10min., or from about 1 g/10 min. to about 30 g/10 min., or from about 1g/10 min. to about 10 g/10 min., or from about 1.3 g/10 min. to about1.9 g/10 min. for example.

The ionomers may exhibit a weight average molecular weight M_(w) (asmeasured by GPC) of from about 100,000 Dalton to about 340,000 Dalton,or from about 170,000 Dalton to about 340,000 Dalton or from about255,000 Dalton to about 330,000 Dalton, for example.

The ionomers may exhibit a number average molecular weight M_(n) (asmeasured by GPC) of from about 45,000 Dalton to about 140,000 Dalton, orfrom about 60,000 Dalton to about 140,000 Dalton or from about 90,000Dalton to about 130,000 Dalton, for example.

The ionomers may exhibit a z average molecular weight M_(z) (as measuredby GPC) of from about 150,000 Dalton to about 630,000 Dalton, or fromabout 310,000 Dalton to about 630,000 Dalton or from about 400,000Dalton to about 600,000 Dalton, for example.

The ionomers may exhibit a polydispersity (Mw/Mn) of from about 1.8 toabout 3.1, or from about 2.0 to about 2.8 or from about 2.2 to about2.8, for example.

The ionomers may exhibit a tensile strength at yield (as measured byASTM D-638) of from about 3,400 psi to about 8,000 psi, or from about5,800 psi to about 8,000 psi or from about 7,400 psi to about 7,900 psi,for example.

The ionomers may exhibit a tensile strength at break (as measured byASTM D-638) of from about 3,200 psi to about 7,900 psi, or from about5,600 psi to about 7,900 psi or from about 7,300 psi to about 7,800 psi,for example.

The ionomers may exhibit a tensile modulus (as measured by ASTM D-638)of from about 410,000 psi to about 490,000 psi, or from about 420,000psi to about 490,000 psi or from about 425,000 psi to about 480,000 psi,for example.

The ionomers may exhibit a flexural strength (as measured by ASTM D-790)of from about 6,000 psi to about 16,500 psi, or from about 11,000 psi toabout 16,500 psi or from about 14,000 psi to about 16,000 psi, forexample.

The ionomers may exhibit a flexural modulus (as measured by ASTM D-790)of from about 410,000 psi to about 520,000 psi, or from about 430,000psi to about 500,000 psi or from about 460,000 psi to about 490,000 psi,for example.

The ionomers are useful as general purpose polystyrene, but may also beused in other applications. For example, the ionomers may be foamed toprepare foamed polystyrene. The ionomers may be used in applicationswhere high temperature performance is desirable such as microwave safedishes and utensils. The ionomers may be used to form other objects suchas containers and as components in automobiles, toys, and the like. Thepolar ionic moieties of the ionomers may enhance their compatibilitywith polyesters such as polyethylene terephthalate and polycarbonate, sothe branched ionomers may be used in blends and alloys with these andother similarly polar polymers.

Of significant interest in foam applications is the reduction of foamweight. However, reduction of weight often leads to detrimental foamproperties. However, embodiments of the invention are capable of formingfoam products having reduced weight without a detrimental change inproperties.

Accordingly, in one or more embodiments, the ionomers are utilized toform foamed polystyrene articles. Such foamed articles may include thoseknown to one skilled in the art, such as insulation and/or packaging.The insulation materials may include foam board or sheet materials, forexample. Molded polystyrene foams are widely used to insulate buildingsand components of buildings. Foam sheets may alternatively bethermoformed into articles, such as trays or containers or may be moldedinto foamed dunnage shapes suitable for packaging applications, forexample.

Alternatively, the ionomers may be utilized in film applications. Filmsinclude blown, oriented or cast films formed by extrusion orco-extrusion or by lamination useful as shrink film, cling film, stretchfilm, sealing films, oriented films, snack packaging, heavy duty bags,grocery sacks, baked and frozen food packaging, medical packaging,industrial liners, and membranes, for example, in food-contact andnon-food contact application.

EXAMPLES

Experimental polymers which are embodiments of the present invention,referred to as Polymer A and Polymer B, were both produced in a pilotplant consisting of two CSTR prepolymerization reactors, four stirredhorizontal plug flow reactors, an upflow preheater as a fifth reactor,followed by devolitization. Polymer A included styrene monomer, 400 ppmof L531 initiator (commercially available from Arkema) and 800 ppm ofzinc dimethacrylate (Saret 634 available from Sartomer Company) as thesecond monomer and 900 ppm of zinc stearate. The second monomer wasdissolved in the styrene monomer prior to entering the reactors. PolymerB included styrene monomer, 150 ppm of L531 initiator (commerciallyavailable from Arkema) and 850 ppm of zinc dimethacrylate (Saret 634available from Sartomer Company) and 650 ppm of zinc stearate. Thesecond monomer was dissolved in the styrene monomer prior to enteringthe reactors. In both cases the zinc stearate was added to the fourthplug flow reactor.

Polymer A was produced with a lower temperature profile to make a lowermelt flow product as compared to Polymer B. The temperature profile ofeach run is shown in Table 1.

TABLE 1 Polymer B Polymer A Reactor temps ° F. 248/260/279/297/307/315/228/238/270/275/290/ 310 295/296 MFI (g/10 min) 3.0 1.6

Example 1

Various foam articles were formed and the resulting properties wereanalyzed. Inventive Polymer A and a comparison Polymer 1, which iscommercially available from TOTAL PETROCHEMICALS USA, Inc. as 585T, werefoamed into foam sheets and evaluated. The properties of the evaluatedpolymers are summarized in Table 2.

TABLE 2 COMPARATIVE POLYMER PROPERTY ASTM UNIT POLYMER 1 A Melt FlowD-1238 g/10 min 1.6 1.6 (200° C.-5 kg) Heat Distortion D-648 ° F. 211209 Vicat Softening D-1525 ° F. 225 223 Tensile Strength D-638 PSI 7,6007,700 Tensile Modulus D-638 PSI (E 5) 4.3 4.6 Flexural Strength D-790PSI 14,200 15,200 Flexural Modulus D-790 PSI (E 5) 4.3 4.8 Density g/cucm 1.04 1.04 Linear Shrinkage D-955 in/in .004-.007 .004-.007 Moisture %<0.1 <0.1 Melt Strength N 0.03 0.035 Mw 300,000 278,000 Mn 120,000110,000 MWD 2.5 2.5

It was observed that that Polymer A ran well on the foam line withlittle process change as compared to the comparison Polymer 1. Inaddition, the Polymer A foamed sheet exhibited from 15-30% greatermodulus and strength as compared to the comparison sheet. A polymerhaving increased modulus and strength may be used to make foam productshaving reduced weight without a detrimental change in properties.Polymer A is a low melt flow product that compares favorably with thecommercially available comparative Polymer 1 and may be able to form enduse articles having comparable physical properties while having reducedpolymer usage and weight.

Example 2

Various blown film samples were formed and the resulting properties wereanalyzed. They were formed from inventive Polymer A; inventive PolymerB; comparison Polymer 1 which is commercially available as 585T fromTOTAL PETROCHEMICALS USA, Inc. having a melt flow rate of 1.6 g/10 min.and comparison Polymer 2 which is commercially available as 535B fromTOTAL PETROCHEMICALS USA, Inc. having a melt flow rate of 4.0 g/10 min.The polymer samples were formed at a blowup ratio of 2:1, a zone 1temperature of 385° F., a zone 2 temperature of 410° F., a zone 3temperature of 420° F. and an adaptor temperature of 400° F. Trial 1formed blown film from neat polymer samples, while Trial 2 formed blownfilm from the polymer samples blended with K-Resin, commerciallyavailable from Chevron-Phillips, in a ratio of 75:25 (75% polymer:25%K-Resin).

The Instron tensile analysis and percent shrinkage data for each neatsample is illustrated in Table 3 below.

TABLE 3 Units Polymer 1 Polymer 2 Polymer B Polymer A Ten. Str. Yld. PSI9459 7980 8701 9783 MD Ten. Str. Break PSI 8354 7979 8629 9253 MDElongation % 4.7 3.8 4.0 4.6 MD Ten. Str. Yld. PSI 4378 5840 4803 4402TD Ten. Str. Break PSI 4473 5825 4803 4392 TD Elongation % 2.4 2.0 2.02.3 TD Shrinkage MD % 75 78 67 75 Shrinkage TD % 20 18 15 18

It was observed that Polymer A exhibited greater machine directiontensile strength (yield and maximum) than the comparative Polymer 1while they had comparable melt flows. It was observed that Polymer Bexhibited greater machine direction tensile strength (yield and maximum)than the comparative Polymer 2 while they had comparable melt flows. Apolymer having increased tensile strength can be used to make filmproducts having reduced weight without a detrimental change inproperties.

The hauloff force for Polymer A and comparative Polymers 1 and 2 weretested and the results are shown in FIG. 3 as Hauloff force vs Hauloffspeed, Inventive Polymer A exhibits greater Hauloff force than eithercomparative Polymer 1 or comparative Polymer 2, again illustratingimproved properties versus a comparative polymer of the same melt flow.A polymer having increased Hauloff can be used to make film productshaving reduced weight without a detrimental change in properties.

The Instron tensile analysis and percent shrinkage data for each blendedsample is illustrated in Table 4 below.

TABLE 4 Polymer 1 Polymer 2 Polymer B Polymer A Units blend blend blendblend Ten. Str. Yld. PSI 6642 6496 6452 7982 MD Ten. Str. Break PSI 55386271 6277 6913 MD Elongation % 3.4 3.7 3.5 4.1 MD Ten. Str. Yld. PSI5526 5344 4230 5088 TD Ten. Str. Break PSI 5436 5300 4218 5006 TDElongation % 3.3 3.1 3.0 3.2 TD Shrinkage MD % 70 55 78 62 Shrinkage TD% 25 15 25 20

The blown film tensile properties are shown in FIGS. 1 and 2.

It was observed that Polymer A exhibited greater machine directiontensile strength (yield and maximum) than the other polymer samples. Itappears that Polymer A further exhibited enhanced synergism whenblended. At a 25% loading, a significant improvement was observed inmachine direction tensile strength while the transverse directionproperties are near or slightly below comparison polymers. A polymerhaving increased tensile strength can be used to make film productshaving reduced weight without a detrimental change in properties.

Each of the appended claims defines a separate invention, which forinfringement purposes is recognized as including equivalents to thevarious elements or limitations specified in the claims. Depending onthe context, all references below to the “invention” may in some casesrefer to certain specific embodiments only. In other cases it will berecognized that references to the “invention” will refer to subjectmatter recited in one or more, but not necessarily all, of the claims.Each of the inventions will now be described in greater detail below,including specific embodiments, versions and examples, but theinventions are not limited to these embodiments, versions or examples,which are included to enable a person having ordinary skill in the artto make and use the inventions when the information in this patent iscombined with available information and technology.

Various terms as used herein are shown below. To the extent a term usedin a claim is not defined below, it should be given the broadestdefinition skilled persons in the pertinent art have given that term asreflected in printed publications and issued patents at the time offiling. Further, unless otherwise specified, all compounds describedherein may be substituted or unsubstituted and the listing of compoundsincludes derivatives thereof.

Embodiments of the invention generally include forming branched aromaticionomers. As used herein, the term “ionomer” is defined as a polymerwith covalent bonds between elements of the polymer chain and ionicbonds between separate chains of the polymer (or as sometimes referredto, polymers containing inter-chain ionic bonding). The ionomersdescribed herein uniquely contain reversible crosslinks. At meltprocessing temperatures, the reversible crosslinks generallydisassociate to later reform as the material cools to its glasstransition temperature.

Use of the term “optionally” with respect to any element of a claim isintended to mean that the subject element is required, or alternatively,is not required. Both alternatives are intended to be within the scopeof the claim. Use of broader terms such as comprises, includes, having,etc. should be understood to provide support for narrower terms such asconsisting of, consisting essentially of, comprised substantially of,etc.

The various embodiments of the present invention can be joined incombination with other inventions of the invention and the listedembodiments herein are not meant to limit the invention. Allcombinations of various inventions of the invention are enabled, even ifnot given in a particular example herein.

While illustrative embodiments have been depicted and described,modifications thereof can be made by one skilled in the art withoutdeparting from the spirit and scope of the disclosure. Where numericalranges or limitations are expressly stated, such express ranges orlimitations should be understood to include iterative ranges orlimitations of like magnitude falling within the expressly stated rangesor limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.;greater than 0.10 includes 0.11, 0.12, 0.13, etc.).

Depending on the context, all references herein to the “invention” mayin some cases refer to certain specific embodiments only. In other casesit may refer to subject matter recited in one or more, but notnecessarily all, of the claims. While the foregoing is directed toembodiments, versions and examples of the present invention, which areincluded to enable a person of ordinary skill in the art to make and usethe inventions when the information in this patent is combined withavailable information and technology, the inventions are not limited toonly these particular embodiments, versions and examples. Also, it iswithin the scope of this disclosure that the embodiments disclosedherein are usable and combinable with every other embodiment disclosedherein, and consequently, this disclosure is enabling for any and allcombinations of the embodiments disclosed herein. Other and furtherembodiments, versions and examples of the invention may be devisedwithout departing from the basic scope thereof and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. A branched aromatic ionomer comprising a product of co-polymerizing a first monomer comprising an aromatic moiety and an unsaturated alkyl moiety and a second monomer wherein the second monomer is selected from a group consisting of zinc di-vinylacetate, zinc di-ethylfumarate: copper diacrylate, copper dimethacrylate, copper di-vinylacetate, copper di-ethylfumarate; aluminum (III) isopropoxide, aluminum triacrylate, aluminum trimethacrylate, aluminum tri-vinylacetate, aluminum tri-ethylfumarate; zirconium tetraacrylate, zirconium tetramethacrylate, zirconium tetra-vinylacetate, zirconium tetra-ethylfumarate, zirconium (IV) butoxide; and mixtures thereof.
 2. The ionomer of claim 1, wherein the branched aromatic ionomer exhibits a melt flow index (as measured by ASTM D-1238) of from 1.0 g/10 min. to 13 g/10 min.
 3. The ionomer of claim 1, wherein the first monomer is selected from the group consisting of styrene, alphamethyl styrene, t-butylstyrene, p-methylstyrene, vinyl toluene, and mixtures thereof.
 4. The ionomer of claim 1, wherein the second monomer is present in amounts of from 10 to 10,000 ppm.
 5. The ionomer of claim 1, wherein the second monomer is present in amounts of from 100 to 2,500 ppm.
 6. The ionomer of claim 1, wherein the ionomer exhibits a weight average molecular weight of from 255,000 Dalton to 330,000 Dalton.
 7. The ionomer of claim 1, wherein the ionomer exhibits a polydispersity of from 1.8 to 3.1.
 8. The ionomer of claim 1, wherein the ionomer exhibits a tensile strength at yield (as measured by ASTM D-638) of from 3,400 psi to 8,000 psi.
 9. The ionomer of claim 1, wherein the ionomer exhibits a tensile strength at break (as measured by ASTM D-638) of from 3,200 psi to 7,900 psi.
 10. The ionomer of claim 1, wherein the ionomer exhibits a flexural strength (as measured by ASTM D-790) of from 6,000 psi to 16,500 psi.
 11. The ionomer of claim 1, wherein the ionomer exhibits a flexural modulus (as measured by ASTM D-790) of from 410,000 psi to 490,000 psi.
 12. A blown film formed by the ionomer of claim
 1. 13. A foamed article formed by the ionomer of claim
 1. 14. A process for preparing a branched aromatic ionomer comprising: co-polymerizing a first monomer comprising an aromatic moiety and an unsaturated alkyl moiety and a second monomer wherein the second monomer is selected from a group consisting of zinc di-vinylacetate, zinc di-ethylfumarate: copper diacrylate, copper dimethacrylate, copper di-vinylacetate, copper di-ethylfumarate; aluminum (III) isopropoxide, aluminum triacrylate, aluminum trimethacrylate, aluminum tri-vinylacetate, aluminum tri-ethylfumarate; zirconium tetraacrylate, zirconium tetramethacrylate, zirconium tetra-vinylacetate, zirconium tetra-ethylfumarate, zirconium (IV) butoxide; and mixtures thereof.
 15. The process of claim 14, wherein the branched aromatic ionomer exhibits a melt flow index (as measured by ASTM D-1238) of from 1.0 g/10 min. to 13 g/10 min.
 16. The process of claim 14, wherein the second monomer is prepared prior to the co-polymerization by admixing components in-line to a reactor or in-situ in a reactor.
 17. The process of claim 14, wherein the second monomer is prepared in-situ in the first monomer.
 18. The process of claim 14, wherein the second monomer is prepared from an unsaturated acid or anhydride and a metal alkoxide.
 19. The process of claim 14, wherein the second monomer is prepared by reacting an organic acid or an anhydride with a metal or metal salt.
 20. The process of claim 14, wherein the first monomer is selected from the group consisting of styrene, alphamethyl styrene, t-butylstyene, p-methylstyrene, vinyl toluene, and mixtures thereof.
 21. The process of claim 14, further comprising the step of admixing the first and second monomers prior to or at the time of the co-polymerization.
 22. The process of claim 14, wherein the first and second monomers are admixed with a solvent prior to co-polymerization.
 23. The process of claim 14, further comprising the steps of foaming the ionomer and using said foamed ionomer to make an article.
 24. The process of claim 14, further comprising the step of making an article with said ionomer.
 25. The process of claim 14, wherein the ionomers are admixed with additives prior to being used in end use applications, and wherein the additives are selected from the group consisting of fire retardants, antioxidants, lubricants, blowing agents, UV stabilizers, antistatic agents, and combinations thereof. 